1. Field of the Invention
This invention pertains to wireless networks generally and, more particularly, to means for maintaining connections between wireless stations and wired networks.
2. Description of the Related Art
Local area networks (LANs) have been used for years and typically consist of nodes interconnected by physical telecommunications media (e.g., coaxial cable, twisted pair wire, or fiber optics). More recently, wireless LANs have become more popular and are now commonly found in both business and home environments.
Rather than having physical telecommunications media connecting devices to the network, wireless LANs use one or more access points (AP's) to transmit data from the network to wireless stations (e.g., wireless-enabled laptops, PDAs and the like) within the AP's basic service area. If a wireless station is located within the basic service area of a particular AP, that wireless station will be able to receive transmissions sent by that AP. An AP (or system using multiple AP's, such as a system comprising multiple AP's at a particular office location or campus) uses a Service Set IDentifier (SSID) to differentiate itself from other AP's that are not part of the system. A user wishing to connect a wireless station to an AP in the system must provide the unique SSID; the wireless station will search for AP's matching the SSID, and then connect to the one having the strongest signal. Once the connection is made, the wireless station is connected to the network.
A problem exists, however, when the AP to which the wireless station is connected loses its network connection. This can happen for a variety of reasons, such as a defect/failure in connectors, cabling, upstream routers or switches, and the like. The connection between the wireless stations and the AP, and the AP and the network, are two independent connections; thus, when the connection between the network and an AP is lost, the connection between the wireless stations and that AP remains. The AP stays connected to each of the users in its area because it has the strongest signal local to the client; all of the AP's in the system use the same SSID and thus the wireless station simply connects (stays connected) to the strongest one. This keeps the client from searching for another access point which may be connected to the network, and thus the wireless stations remain disconnected from the network.
Accordingly, it would be desirable to have a method and system for alerting wireless stations of a disconnection of an AP from the network, so that alternate APs could be searched for and accessed.